Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

error/E0691: include alignment in error message #113913

Merged
merged 1 commit into from
Jul 21, 2023
Merged

error/E0691: include alignment in error message #113913

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 2 additions & 1 deletion compiler/rustc_error_codes/src/error_codes/E0691.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,8 @@ struct ForceAlign32;

#[repr(transparent)]
struct Wrapper(f32, ForceAlign32); // error: zero-sized field in transparent
// struct has alignment larger than 1
// struct has alignment of 32, which
// is larger than 1
```

A transparent struct, enum, or union is supposed to be represented exactly like
Expand Down
29 changes: 19 additions & 10 deletions compiler/rustc_hir_analysis/src/check/check.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1078,9 +1078,9 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>)
// We are currently checking the type this field came from, so it must be local
let span = tcx.hir().span_if_local(field.did).unwrap();
let zst = layout.is_ok_and(|layout| layout.is_zst());
let align1 = layout.is_ok_and(|layout| layout.align.abi.bytes() == 1);
let align = layout.ok().map(|layout| layout.align.abi.bytes());
if !zst {
return (span, zst, align1, None);
return (span, zst, align, None);
}

fn check_non_exhaustive<'tcx>(
Expand Down Expand Up @@ -1115,30 +1115,39 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>)
}
}

(span, zst, align1, check_non_exhaustive(tcx, ty).break_value())
(span, zst, align, check_non_exhaustive(tcx, ty).break_value())
});

let non_zst_fields = field_infos
.clone()
.filter_map(|(span, zst, _align1, _non_exhaustive)| if !zst { Some(span) } else { None });
.filter_map(|(span, zst, _align, _non_exhaustive)| if !zst { Some(span) } else { None });
let non_zst_count = non_zst_fields.clone().count();
if non_zst_count >= 2 {
bad_non_zero_sized_fields(tcx, adt, non_zst_count, non_zst_fields, tcx.def_span(adt.did()));
}
let incompatible_zst_fields =
field_infos.clone().filter(|(_, _, _, opt)| opt.is_some()).count();
let incompat = incompatible_zst_fields + non_zst_count >= 2 && non_zst_count < 2;
for (span, zst, align1, non_exhaustive) in field_infos {
if zst && !align1 {
struct_span_err!(
for (span, zst, align, non_exhaustive) in field_infos {
if zst && align != Some(1) {
let mut err = struct_span_err!(
tcx.sess,
span,
E0691,
"zero-sized field in transparent {} has alignment larger than 1",
adt.descr(),
)
.span_label(span, "has alignment larger than 1")
.emit();
);

if let Some(align_bytes) = align {
err.span_label(
span,
format!("has alignment of {align_bytes}, which is larger than 1"),
);
} else {
err.span_label(span, "may have alignment larger than 1");
}

err.emit();
}
if incompat && let Some((descr, def_id, args, non_exhaustive)) = non_exhaustive {
tcx.struct_span_lint_hir(
Expand Down
8 changes: 4 additions & 4 deletions tests/ui/repr/repr-transparent.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -20,13 +20,13 @@ error[E0691]: zero-sized field in transparent struct has alignment larger than 1
--> $DIR/repr-transparent.rs:36:32
|
LL | struct NontrivialAlignZst(u32, [u16; 0]);
| ^^^^^^^^ has alignment larger than 1
| ^^^^^^^^ has alignment of 2, which is larger than 1

error[E0691]: zero-sized field in transparent struct has alignment larger than 1
--> $DIR/repr-transparent.rs:42:24
|
LL | struct GenericAlign<T>(ZstAlign32<T>, u32);
| ^^^^^^^^^^^^^ has alignment larger than 1
| ^^^^^^^^^^^^^ has alignment of 32, which is larger than 1

error[E0084]: unsupported representation for zero-variant enum
--> $DIR/repr-transparent.rs:44:1
Expand Down Expand Up @@ -66,13 +66,13 @@ error[E0691]: zero-sized field in transparent enum has alignment larger than 1
--> $DIR/repr-transparent.rs:71:14
|
LL | Foo(u32, [u16; 0]),
| ^^^^^^^^ has alignment larger than 1
| ^^^^^^^^ has alignment of 2, which is larger than 1

error[E0691]: zero-sized field in transparent enum has alignment larger than 1
--> $DIR/repr-transparent.rs:76:11
|
LL | Foo { bar: ZstAlign32<T>, baz: u32 }
| ^^^^^^^^^^^^^^^^^^ has alignment larger than 1
| ^^^^^^^^^^^^^^^^^^ has alignment of 32, which is larger than 1

error[E0690]: transparent union needs at most one non-zero-sized field, but has 2
--> $DIR/repr-transparent.rs:85:1
Expand Down